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我希望通过划分它们来修改 xml 文件中的值。

我需要将值除以se:SvgParameter[name="stroke-width"]3.6 se:Size。我在 Python.org 上找到了本教程，修改 XML 文件，但它似乎不起作用，我在这里找不到类似的东西。任何帮助或观点将不胜感激！

这是一些 XML 示例，但我希望能够在包含多个文件的文件夹中输出脚本并让它转换所有文件。

XML:

<?xml version="1.0" encoding="ISO-8859-1"?>
<StyledLayerDescriptor version="1.1.0" xmlns="http://www.opengis.net/sld" xmlns:ogc="http://www.opengis.net/ogc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.opengis.net/sld http://schemas.opengis.net/sld/1.1.0/StyledLayerDescriptor.xsd" xmlns:se="http://www.opengis.net/se">
  <NamedLayer>
    <se:Name>QGIS_SLD_ScaleProblem</se:Name>
    <se:Description>
      <se:Title>QGIS_SLD_ScaleProblem</se:Title>
      <se:Abstract>This SLD is in Pixels, but QGIS will read it as mm</se:Abstract>
    </se:Description>
    <UserStyle>
      <se:Name>QGIS_SLD_ScaleProblem</se:Name>
      <se:FeatureTypeStyle>
        <se:Rule>
          <se:Name>QGIS_SLD_ScaleProblem_Line</se:Name>
          <se:LineSymbolizer>
            <se:Name>Line</se:Name>
            <se:Stroke>
              <se:SvgParameter name="stroke">#FF0000</se:SvgParameter>
              <se:SvgParameter name="stroke-width">36</se:SvgParameter>
            </se:Stroke>
          </se:LineSymbolizer>
        </se:Rule>
        <se:Rule>
          <se:Name>QGIS_SLD_ScaleProblem_Point</se:Name>
          <se:PointSymbolizer>
            <se:Name>Point</se:Name>
            <se:Graphic>
             <se:Mark>
              <se:WellKnownName>circle</se:WellKnownName>
              <se:Fill>
               <se:SvgParameter name="fill">#FF0000</se:SvgParameter>
              </se:Fill>
             </se:Mark>
             <se:Size>36</se:Size>
            </se:Graphic>
          </se:PointSymbolizer>
        </se:Rule>
      </se:FeatureTypeStyle>
    </UserStyle>
  </NamedLayer>
</StyledLayerDescriptor>

代码：

import xml.etree.ElementTree as ET
from lxml import etree

tree = ET.parse('QGIS-SLD-ScaleProblem_Line.sld')
root = tree.getroot()

# To check that the script is reading the correct file
print("SLD file", root[0][0].text, "loaded.")

# Registers namespaces to prevent them being filled with defaults
ET.register_namespace('', "http://www.opengis.net/sld")
ET.register_namespace('ogc', "http://www.opengis.net/ogc")
ET.register_namespace('xsi', "http://www.w3.org/2001/XMLSchema-instance")
ET.register_namespace('xlink', "http://www.w3.org/1999/xlink")
ET.register_namespace('schemaLocation', "http://www.opengis.net/sld http://schemas.opengis.net/sld/1.1.0/StyledLayerDescriptor.xsd")
ET.register_namespace('se', "http://www.opengis.net/se")

# This section "should" search the XML for se:SvgParameter name="stroke-width" and se:Size and divide the value by 3.6
for SvgParameter in root.iter('SvgParameter'):
    new_SvgParameter = int(SvgParameter.text) / 3.6
    SvgParameter.text = str(new_SvgParameter)
for Size in root.iter('Size'):
    new_Size= int(Size.text) / 3.6
    Size.text = str(new_Size)

tree.write("GIS-SLD-ScaleFixed.sld", xml_declaration=True, encoding='ISO-8859-1')

我看过的答案：

4

1 回答 1

0

考虑一下XSLT是一种专门用于转换 XML 文件的语言。并且 Python 的lxml模块可以运行 XSLT 1.0 脚本。此外，XSLT 可以在 Python 之外运行，因此具有可移植性。

只需调用身份转换即可按原样复制整个文档，然后在选定节点上运行划分。这种方法不需要for循环或if逻辑。

XSLT （另存为 .xsl 文件，一种特殊的格式良好的 XML 文件）

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                              xmlns:se="http://www.opengis.net/se">                               
  <xsl:output indent="yes"/>
  <xsl:strip-space elements="*"/>

  <xsl:template match="@*|node()">
    <xsl:copy>
      <xsl:apply-templates select="@*|node()"/>
    </xsl:copy>
  </xsl:template>

  <xsl:template match="se:SvgParameter[@name='stroke-width']|se:Size">
    <xsl:copy>
        <xsl:apply-templates select="@*"/>
        <xsl:value-of select="format-number(text(), '#') div 3.6"/>
    </xsl:copy>
  </xsl:template>

</xsl:stylesheet>

Python （在循环中为多个文件迭代下面的过程）

import lxml.etree as et

# LOAD XML AND XSL
doc = et.parse('Input.xml')
xsl = et.parse('XSLTScript.xsl')

# TRANSFORM
transform = et.XSLT(xsl)
result = transform(doc)

# OUTPUT TO SCREEN    
print(result)

# OUTPUT TO FILE
with open('Output.xml', 'wb') as f:
    f.write(result)

输出

<?xml version="1.0"?>
<StyledLayerDescriptor xmlns="http://www.opengis.net/sld" xmlns:ogc="http://www.opengis.net/ogc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:se="http://www.opengis.net/se" version="1.1.0" xsi:schemaLocation="http://www.opengis.net/sld http://schemas.opengis.net/sld/1.1.0/StyledLayerDescriptor.xsd">
  <NamedLayer>
    <se:Name>QGIS_SLD_ScaleProblem</se:Name>
    <se:Description>
      <se:Title>QGIS_SLD_ScaleProblem</se:Title>
      <se:Abstract>This SLD is in Pixels, but QGIS will read it as mm</se:Abstract>
    </se:Description>
    <UserStyle>
      <se:Name>QGIS_SLD_ScaleProblem</se:Name>
      <se:FeatureTypeStyle>
        <se:Rule>
          <se:Name>QGIS_SLD_ScaleProblem_Line</se:Name>
          <se:LineSymbolizer>
            <se:Name>Line</se:Name>
            <se:Stroke>
              <se:SvgParameter name="stroke">#FF0000</se:SvgParameter>
              <se:SvgParameter name="stroke-width">10</se:SvgParameter>
            </se:Stroke>
          </se:LineSymbolizer>
        </se:Rule>
        <se:Rule>
          <se:Name>QGIS_SLD_ScaleProblem_Point</se:Name>
          <se:PointSymbolizer>
            <se:Name>Point</se:Name>
            <se:Graphic>
              <se:Mark>
                <se:WellKnownName>circle</se:WellKnownName>
                <se:Fill>
                  <se:SvgParameter name="fill">#FF0000</se:SvgParameter>
                </se:Fill>
              </se:Mark>
              <se:Size>10</se:Size>
            </se:Graphic>
          </se:PointSymbolizer>
        </se:Rule>
      </se:FeatureTypeStyle>
    </UserStyle>
  </NamedLayer>
</StyledLayerDescriptor>
于 2017-09-12T14:52:52.163 回答